The present invention relates to a safety device for vehicles. In particular, the present invention is intended to detect a state in a vehicle which corresponds to the vehicle rotating about its longitudinal axis (so called xe2x80x9croll-overxe2x80x9d). The present invention also relates to a method utilizing such safety device.
In connection with motor vehicles, there are certain kinds of accidents where the vehicle tilts so heavily that it rolls about its longitudinal axis. This, of course, causes great risks of injuries to those travelling in the vehicle. Recently, safety systems have thus been designed which comprise a sensor arranged to detect the presence of such a xe2x80x9croll-overxe2x80x9d state. Such a sensor can be connected to a control unit, which in turn is connected to some kind of protective device, which can be activated to protect those travelling in the vehicle when the vehicle rolls over. An example of such a safety device is a safety bar intended for open-top vehicles, which during roll-over is unfolded from a folded-away position to a position where it extends across the passenger compartment, and thus protects the passengers.
For reasons of safety, it is desirable to detect this roll-over state in a reliable manner. In particular, it must be possible to detect such a state at an early stage during an accident, and in a manner such that it can be separated from other similar states of the vehicle. In this way, it is possible to prevent unnecessary activation of safety devices in the vehicle.
In connection with safety systems of the above-mentioned type, it is known to utilize a sensor which detects the angle of inclination of the vehicle relative to the horizontal plane. If the inclination of the vehicle exceeds a certain predetermined threshold value, a signal can be generated which in turn activates a safety device.
A previously known system for detecting a roll-over state in a vehicle, and for activation of a safety bar if such a state is present, is shown in document European Patent No. 430,813. This system comprises a sensor of the gyrometer-kind, and accelerometers for detecting side and vertical acceleration of the vehicle. Using the signals from the respective sensors, the system can thus determine whether the vehicle is about to roll over. In particular, the angular or rotational speed of the vehicle is detected using the gyrometer, i.e. relative to the horizontal plane. Additionally, the system is arranged to determine whether the ratio between the side and the vertical acceleration exceeds a certain threshold value. If this is the case, the signal is integrated with respect to the angular speed which is detected using the gyrometer. If the signal which is obtained from this integration, and which indicates a value of the current angle of the vehicle, exceeds a certain threshold value, a safety device in the form of a safety bar will be activated.
However, although this previously known system does, in principle, provide an efficient function, it has a drawback in that it does not always sufficiently reliably detect whether the vehicle is about to roll over. Furthermore, there is also a risk that this state is not detected rapidly enough during the course of an accident.
The object of the present invention is to provide an improved device for quick and reliable detection of a rollover-state in a vehicle with, in particular, the above-mentioned drawbacks being eliminated.
In accordance with the present invention, this and other objects have now been realized by the invention of a safety device for detecting the rotation of a vehicle having a longitudinal axis, a transverse axis and a steering wheel comprising angular position means for determining the angular position and angular speed of rotation of the vehicle about at least one of the longitudinal axis and the transverse axis, a control unit for comparing the angular position and angular speed of rotation with predetermined threshold values for the angular position and the angular speed of rotation, at least one of the threshold values being variable and based upon at least one predetermined operational condition of the vehicle, and at least one protective device actuatable by the control unit based upon the comparison.
In accordance with one embodiment of the safety device of the present invention, the control unit includes means for comparing the angular speed of rotation about the longitudinal axis with a first predetermined threshold value, and if the angular speed of rotation about the longitudinal axis exceeds the first predetermined threshold value, comparing the angular position about the longitudinal axis with a second predetermined threshold value, the second predetermined threshold value being variable and based upon the magnitude of the angular speed of rotation, and if the angular position about the longitudinal axis exceeds the second predetermined threshold value, actuating the at least one protective device.
In accordance with another embodiment of the safety device of present invention, the safety device includes a first transducer for determining the side acceleration of the vehicle, the control unit including means for comparing the side acceleration to a third predetermined threshold value and if the side acceleration exceeds the predetermined threshold value, comparing the angular position about the longitudinal axis with a fourth predetermined value, the fourth predetermined threshold value being variable and based upon the side acceleration, and if the angular position about the longitudinal axis exceeds the fourth predetermined threshold value, calculating the time during which the side acceleration has exceeded the third predetermined threshold value, comparing the time during which the side acceleration has exceeded the third predetermined threshold value with a fifth predetermined threshold value, the fifth predetermined threshold value being variable and based upon the side acceleration and the angular position, and if the time during which the side acceleration has exceeded the third predetermined threshold value exceeds the fifth predetermined threshold value, actuating the at least one protective device.
In accordance with another embodiment of the safety device of the present invention, the safety device includes a second transducer for determining the angular position of the steering wheel, and a third transducer for determining the velocity of the vehicle, the control unit including means for comparing the angular position about the longitudinal axis with a sixth predetermined threshold value, and if the angular position about the longitudinal axis exceeds the sixth predetermined threshold value, comparing the velocity of the vehicle with a seventh predetermined threshold value, the seventh predetermined threshold value being variable and based upon the angular position about the longitudinal axis, and if the velocity of the vehicle exceeds the seventh predetermined threshold value, comparing the angular position of the steering wheel with an eighth predetermined threshold value, the eighth predetermined threshold value being variable and based upon the angular position and the velocity of the vehicle, and if the angular position of the steering wheel exceeds the eighth predetermined threshold value, actuating the at least one protective device. Preferably, the control unit includes means for determining the angular velocity of the steering wheel with respect to the direction of turning of the steering wheel, and for comparing the angular position about the longitudinal axis with a ninth predetermined threshold value, and if the angular position about the longitudinal axis exceeds the ninth predetermined threshold value, comparing the speed of the vehicle with a tenth predetermined threshold value, the tenth predetermined threshold value being variable and based upon the angular position about the longitudinal axis, and if the speed of the vehicle exceeds the tenth predetermined threshold value, comparing the angular velocity of the steering wheel with an eleventh predetermined threshold value, the eleventh predetermined threshold value being variable and based upon the angular position and the absolute value of the speed of the vehicle, and if the angular velocity of the steering wheel exceeds the eleventh predetermined threshold value, actuating the at least one protective device.
In accordance with another embodiment of the safety device of the present invention, the control unit includes means for comparing the angular velocity about the transverse axis with a twelfth predetermined threshold value, and if the angular velocity about the transverse axis exceeds the twelfth predetermined threshold value, comparing the angular velocity about the transverse axis with a thirteenth predetermined threshold value, the thirteenth predetermined threshold value being variable and based upon the angular velocity, and if the angular velocity about the transverse axis exceeds the thirteenth predetermined threshold value, actuating the at least one protective device.
In accordance with another embodiment of the safety device of the present invention, the safety device includes a third transducer for determining the acceleration of the vehicle in the longitudinal direction, the control unit including means for comparing the acceleration with a fourteenth predetermined threshold value, and if the acceleration exceeds the fourteenth predetermined threshold value, comparing the angular position about the transverse axis with a fifteenth predetermined threshold value, the fifteenth predetermined threshold value being variable and based upon the acceleration, and if the angular position about the transverse axis exceeds the fifteenth predetermined threshold value, comparing the time during which the acceleration exceeds the fourteenth predetermined threshold value with a sixteenth predetermined threshold value, the sixteenth predetermined threshold value being variable and based upon the acceleration and the angular position about the transverse axis, and if the time during which the acceleration exceeds the fourteenth predetermined threshold value exceeds the sixteenth predetermined threshold value, actuating the at least one protective device.
In accordance with another embodiment of the safety device of the present invention, the control unit includes means for comparing the angular acceleration about the transverse axis with a seventeenth predetermined threshold value, and if the angular acceleration about the transverse axis exceeds the seventeenth predetermined threshold value, comparing the time during which the angular acceleration about the transverse axis exceeds the seventeenth predetermined threshold value with an eighteenth predetermined threshold value, the eighteenth predetermined threshold value being variable and based upon the angular acceleration about the transverse axis, and if the time during which the angular acceleration about the transverse axis exceeds the seventeenth predetermined threshold value exceeds the eighteenth predetermined threshold value, comparing the angular velocity about the longitudinal axis with a nineteenth predetermined threshold value, the nineteenth predetermined threshold value being variable and based upon the angular acceleration about the transverse axis and the time during which the angular acceleration about the transverse axis exceeds the seventeenth predetermined threshold value, and if the angular velocity about the longitudinal axis exceeds the nineteenth predetermined threshold value, comparing the angular position of the vehicle about the longitudinal axis with a twentieth predetermined threshold value, the twentieth predetermined threshold value being variable and based upon the angular acceleration about the transverse axis, the time during which the angular acceleration exceeds the seventeenth predetermined threshold value, and the angular velocity about the longitudinal axis, and if the angular position about the longitudinal axis exceeds the twentieth predetermined threshold value, actuating the at least one protective device.
In accordance with another embodiment of the safety device of the present invention, the control unit includes means for comparing the angular acceleration of the vehicle about the transverse axis with a twenty-first predetermined threshold value, and if the angular acceleration about the transverse axis exceeds the twenty-first predetermined threshold value, comparing the time during which the angular acceleration exceeds the twenty-first predetermined threshold value with a twenty-second predetermined threshold value, the twenty-second predetermined threshold value being variable and based upon the angular acceleration about the transverse axis, and if the time during which the angular acceleration exceeds the twenty-first predetermined threshold value exceeds the twenty-second predetermined threshold value, comparing the angular velocity about the transverse axis with a twenty-third predetermined threshold value, the twenty-third predetermined threshold value being variable and based upon the angular acceleration about the transverse axis and the time during which the angular acceleration about the transverse axis exceeds the twenty-first predetermined threshold value, and if the angular velocity about the transverse axis exceeds the twenty-third predetermined threshold value, comparing the angular position of the vehicle with respect to the transverse axis with a twenty-fourth predetermined threshold value, the twenty-fourth predetermined threshold value being variable and based upon the angular acceleration about the transverse axis, the time during which the angular acceleration about the transverse axis exceeds the twenty-first predetermined threshold value and the angular velocity about the transverse axis, and if the angular position with respect to the transverse axis exceeds the twenty-fourth predetermined threshold value, actuating the at least one protective device.
In accordance with another embodiment of the safety device of the present invention, the angular position means comprises at least one micromechanical gyro for detecting the angular velocity of the vehicle about the at least one of the longitudinal and transverse axes, the micromechanical gyro being connected to the control unit.
In accordance with the present invention, a safety device has been provided for detecting the rotation of a vehicle having a longitudinal axis and a transverse axis, comprising a transducer for determining the side acceleration of the vehicle, a control unit for comparing the side acceleration to a first predetermined threshold value, and if the side acceleration exceeds the first predetermined threshold value, comparing the time during which the side acceleration exceeds the first predetermined threshold value with a second predetermined threshold value, and at least one protective device actuatable by the control unit if the time during which the side acceleration exceeds the first predetermined threshold value exceeds the second predetermined threshold value. Preferably, the second predetermined threshold value is variable and based upon the side acceleration.
In accordance with the present invention, a safety device has been devised for detecting the rotation of a vehicle having a longitudinal axis comprising a transducer for determining the angular acceleration of the vehicle about the longitudinal axis, a control unit for comparing the angular acceleration about the longitudinal axis with a first predetermined threshold value, the first predetermined threshold value being variable and based upon the positional energy of the vehicle which must be overcome for the vehicle to roll over, and at least one protective device actuatable by the control unit if the angular acceleration about the longitudinal axis exceeds the first predetermined threshold value.
In accordance with the method of the present invention, a method has been devised for detecting the rotation of a vehicle including a longitudinal axis, a transverse axis and a steering wheel, the method comprising determining the angular position and the angular speed of rotation of the vehicle about at least one of the longitudinal axis and the transverse axis, comparing the angular position and the angular speed of rotation with predetermined threshold values for the angular position and the angular speed of rotation, at least one of the threshold values being variable and based upon at least one predetermined operational condition for the vehicle, and actuating at least one protective device based upon the comparison. Preferably, the method includes comparing the angular velocity of the vehicle about the longitudinal axis with a first predetermined threshold value, and if the angular velocity about the longitudinal axis exceeds the first predetermined threshold value, comparing the angular position of the vehicle about the longitudinal axis with a second predetermined threshold value, the second predetermined threshold value being variable and based upon the angular velocity about the longitudinal axis, and if the angular position about the longitudinal axis exceeds the second predetermined threshold value, actuating the at least one protective device.
In accordance with one embodiment of the method of the present invention, the method includes comparing the side acceleration of the vehicle with a third predetermined threshold value, and if the side acceleration exceeds the third predetermined threshold value, comparing the angular position of the vehicle with a fourth predetermined threshold value, the fourth predetermined threshold value being variable and based upon the side acceleration, and if the angular position of the vehicle about the transverse axis exceeds the fourth predetermined threshold value, comparing the time during which the side acceleration exceeds the third predetermined threshold value exceeds a fourth predetermined threshold value, the fourth predetermined threshold value being variable and based upon the side acceleration and the angular position of the vehicle about the transverse axis, and if the time during which the side acceleration exceeds the third predetermined threshold value exceeds the fourth predetermined threshold value, actuating the at least one protective device.
In accordance with another embodiment of the method of the present invention, the method includes comparing the angular position of the vehicle about the longitudinal axis with a fifth predetermined threshold value, and if the angular position about the longitudinal axis exceeds the fifth predetermined threshold value, comparing the absolute value of the velocity of the vehicle in the longitudinal direction with a sixth predetermined threshold value, the sixth predetermined threshold value being variable and based upon the angular position of the vehicle about the longitudinal axis, and if the absolute value of the velocity in the longitudinal direction exceeds the sixth predetermined threshold value, comparing the angular position of the steering wheel with a seventh predetermined threshold value, the seventh predetermined threshold value being variable and based upon the angular position of the vehicle about the longitudinal axis and the absolute value of the velocity of the vehicle in the longitudinal direction, and if the angular position of the steering wheel exceeds the seventh predetermined threshold value, actuating the at least one protective device.
In accordance with another embodiment of the method of the present invention, the method includes comparing the angular position of the vehicle about the longitudinal axis with an eighth predetermined threshold value, and if the angular position of the vehicle about the longitudinal axis exceeds the eighth predetermined threshold value, comparing the absolute value of the velocity of the vehicle in the longitudinal direction with a ninth predetermined threshold value, the ninth predetermined threshold value being variable and based upon the angular position of the vehicle about the longitudinal axis, and if the absolute value of the velocity of the vehicle in the longitudinal direction exceeds the ninth predetermined threshold value, comparing the angular velocity of the steering wheel with a tenth predetermined threshold value, the tenth predetermined threshold value being variable and based upon the angular position of the vehicle about the longitudinal axis and the absolute value of the velocity of the vehicle in the longitudinal direction, and if the angular velocity of the steering wheel exceeds the tenth predetermined threshold value, actuating the at least one protective device.
In accordance with another embodiment of the method of the present invention, the method includes comparing the angular velocity of the vehicle about the transverse axis with an eleventh predetermined threshold value, and if the angular velocity of the vehicle about the transverse axis exceeds the eleventh predetermined threshold value, comparing the angular position of the vehicle about the transverse axis with a twelfth predetermined threshold value, the twelfth predetermined threshold value being variable and based upon the magnitude of the angular velocity of the vehicle about the transverse axis, and if the angular position of the vehicle about the transverse axis exceeds the twelfth predetermined threshold value, actuating the at least one protective device.
In accordance with another embodiment of the method of the present invention, the method includes comparing the acceleration of the vehicle in the longitudinal direction with a thirteenth predetermined threshold value, and if the acceleration of the vehicle in the longitudinal direction exceeds the thirteenth predetermined threshold value, comparing the angular position of the vehicle about the transverse axis with a fourteenth predetermined threshold value, the fourteenth predetermined threshold value being variable and based upon the acceleration of the vehicle in the longitudinal direction, and if the angular position of the vehicle about the transverse axis exceeds the fourteenth predetermined threshold value, comparing the time during which the acceleration of the vehicle in the longitudinal direction exceeds the thirteenth predetermined threshold value with a fifteenth predetermined threshold value, the fifteenth predetermined threshold value being variable and based upon the acceleration of the vehicle in the longitudinal direction and the angular position of the vehicle, and if the time during which the acceleration of the vehicle in the longitudinal direction exceeds the thirteenth predetermined threshold value exceeds the fifteenth predetermined threshold value, actuating the at least one protective device.
In accordance with another embodiment of the method of the present invention, the method includes comparing the angular acceleration of the vehicle in the longitudinal direction with a sixteenth predetermined threshold value, and if the angular acceleration of the vehicle in the longitudinal direction exceeds the sixteenth predetermined threshold value, comparing the time during which the angular acceleration of the vehicle in the longitudinal direction exceeds the sixteenth predetermined threshold value with a seventeenth predetermined threshold value, the seventeenth predetermined threshold value being variable and based upon the angular acceleration of the vehicle in the longitudinal direction, and if the time during which the angular acceleration of the vehicle in the longitudinal direction exceeds the seventeenth predetermined threshold value, comparing the angular velocity of the vehicle about the longitudinal axis with an eighteenth predetermined threshold value, the eighteenth predetermined threshold value being variable and based upon the angular acceleration of the vehicle in the longitudinal direction and the time during which the angular acceleration in the longitudinal direction exceeds the sixteenth predetermined threshold value, and if the angular velocity of the vehicle about the longitudinal axis exceeds the eighteenth predetermined threshold value, comparing the angular position of the vehicle about the longitudinal axis with a nineteenth predetermined threshold value, the nineteenth predetermined threshold value being variable and based upon the angular acceleration of the vehicle in the longitudinal direction, the time during which the angular acceleration of the vehicle in the longitudinal direction exceeds the sixteenth predetermined threshold value and the angular velocity of the vehicle about the longitudinal axis, and if the angular position of the vehicle about the longitudinal axis exceeds the nineteenth predetermined threshold value, actuating the at least one protective device.
In accordance with another embodiment of the method of the present invention, the method includes comparing the angular acceleration of the vehicle in the transverse direction with a twentieth predetermined threshold value, and if the angular acceleration of the vehicle in the transverse direction exceeds the twentieth predetermined threshold value, comparing the time during which the angular acceleration of the vehicle in the transverse direction exceeds the twentieth predetermined threshold value with a twenty-first predetermined threshold value, the twenty-first predetermined threshold value being variable and based upon the angular acceleration of the vehicle in the transverse direction, and if the time during which the angular acceleration of the vehicle in the transverse direction exceeds the twentieth predetermined threshold value exceeds the twenty-first predetermined threshold value, comparing the angular velocity of the vehicle about the longitudinal axis with a twenty-second predetermined threshold value, the twenty-second predetermined threshold value being variable and based upon the angular acceleration of the vehicle in the transverse direction and the time during which the angular acceleration of the vehicle in the transverse direction exceeds the twentieth predetermined threshold value, and if the angular velocity of the vehicle about the longitudinal axis exceeds the twenty-second predetermined threshold value, comparing the angular position of the vehicle about the transverse axis with a twenty-third predetermined threshold value, the twenty-third predetermined threshold value being variable and based upon the angular acceleration of the vehicle in the transverse direction, the time during which the angular acceleration of the vehicle in the transverse direction exceeds the twentieth predetermined threshold value and the angular velocity of the vehicle about the longitudinal axis, and if the angular position of the vehicle and of the transverse axis exceeds the twenty-third predetermined threshold value, actuating the at least one protective device.
In accordance with the present invention, a method has also been devised for detecting the rotation of a vehicle including a longitudinal axis and a transverse axis, the method comprising determining the side acceleration of the vehicle, comparing the side acceleration of the vehicle with a third predetermined threshold value, and if the side acceleration exceeds the third predetermined threshold value, comparing the time during which the side acceleration exceeds the third predetermined threshold value with a fourth predetermined threshold value, and actuating at least one protective device if the time during which the side acceleration exceeds the third predetermined threshold value exceeds the fourth predetermined threshold value.
In accordance with the present invention, a method has been devised for detecting the rotation of a vehicle including a longitudinal axis, the method comprising determining the angular acceleration of the vehicle about the longitudinal axis, determining a value corresponding to the rotational energy of the vehicle about the longitudinal axis, comparing the value of the rotational energy of the vehicle with a predetermined threshold value, the predetermined threshold value being variable and based upon the positional energy of the vehicle which must be overcome for the vehicle to roll over, and actuating at least one protective device if the value of the rotational energy exceeds the predetermined threshold value.
The present invention is intended to detect rotation of a vehicle about its longitudinal and/or its latitudinal or transverse axis, and for the activation of at least one safety device in response to said detection. The present invention comprises means for determining the angular position of the vehicle about at least one of these axes, and the angular velocity of rotation, and a control unit which is arranged for the above-mentioned activation if certain predetermined threshold conditions relative to the operational state of the vehicle are fulfilled. The present invention is based on the principle that at least one of the threshold conditions is variable, and can be chosen depending on at least one predetermined operational state of the vehicle. In this manner, a quick and reliable detection of the roll-over state is obtained.
In a preferred embodiment of the present invention, a micromechanical gyro is utilized to detect the angular velocity of rotation of the vehicle.